Method and apparatus for bridging well fissures



May 24, 1955 H. L. FrwnNlNG METHOD AND APPARATUS FOR BRIDGING' WELLFISSURES Filed April 9, 1951 2 Sheets-Sheet l INVENTOR.

BY a /f'Attmqs o o nl@ Homer L.. Twin/'ng May 24, 1955 H. L. TwxNlNGMETHOD AND APPARATUS FOR BRIDGING WELL FISSURES Filed April 9, 1951 2Sheets-Sheet 2 Homer L. Twin/'ng NVENTOR.

Q BY WWW MW United States Patent O li/IETHOD AND APPARATUS FOR BRIDGINGWELL FISSURES Homer L. Twining, San Antonio, Tex.

Application April 9, 1951, Serial No. 220,018

s Claims. (ci. 16s-2z) The present invention relates to a new and usefulmethod for bridging fissures or cavities encountered during the drillingof wells and to apparatus particularly adapted for practicing themethod.

The primary object ofl this invention is to devise a method andapparatus for sealing or closing oi'r fissures or cavities from a wellhole, which will require a minimum of time and materials.

Another important object of this invention is to prevent the loss ofdrilling mud or the dilution of the same during drilling operations.

Still another important object of this invention is to avoid waste ofsealing materials or cementitious materials used in sealing oif fissuresby preventing the passage of successive quantities of these materialsinto the fissure or cavity.

A further object of this invention is to devise a method for realizingthe above objects, which will be readily utilized by those possessingthe customary and expected skill of those normally in charge of orconducting drilling operations.

Yet another object of this invention is to devise an apparatus forpracticing the method of this invention which will be simple andinexpensive, and which Will, to a large extent, consist of materialscustomarily at hand during drilling operations.

`It is still a further object of this invention to devise a method andapparatus for providing a very strong and reliable seal that will lastindefinitely, and which may be readily penetrated by the drill forextending the bore to greater depths.

A meritorious feature of the method of this invention resides in thefact that a wide range of objects may be used for bridging a lissure.

A further feature of the invention resides in the fact that the bridgingmaterial is expanded toa position in which the same will constitute. asubstantial barrier'to passage of sealing material therethrough andfurther into the fissure, and form a skeletal supporting framework forsupporting the sealing material. Y.

Another important feature of the present invention resides in the factthat the same may. be utilized with equal facility in oil, gas or Waterwells. i

Final important features o f the present invention to be specilicallyenumerated herein reside in the various forms of bridging materialillustrated herein, as well as the various forms of construction forurging the bridgingmaterial to expanded position. j

These, together with various ancillary features and objects of theinvention which will later become apparent as'the followingdescriptionrprocee'ds, are attained by the present' invention, preferredembodiments-of which havebeen illustrated by way of example only in theaccompanying drawings, wherein: f

Figures 1 4, inclusive, are views,

ing ther-method fof the 'present invention, .whenv plants or vegetablebers are used in bridging the fissure;

partially` in section,` illustrative of sequential stages passedthr'ough'in-practic- ICC Figure 5-7, inclusive, are sectional views illustratinga modilied form of the invention and showing the apparatus used and thesequential steps in utilizing such apparatus in sealing off a cavity;and,

Figure 8 is a perspective view of a still further modified form of theapparatus suitable for use in practicing the broad method of the presentinvention.

The method of the present invention encompasses broadly the steps ofsubjecting bridging material, the desired characteristics of which willbe subsequently apparent, to a force tending to expand the samelaterally, and while restraining such material against lateral eX-pansion, inserting the same in a well hole and moving the same to aposition adjacent a fissure or cavity to be sealed, and then removingthe restrainnig force and allowing the material to expand laterally to aposition bridging the fissure or cavity. Usually it is desired tosupplement the sealing effect of the bridging material, inasmuch as suchbridging material may not be impervious to the passage of fluidstherethrough, by the application of a sealing material, preferably of acementitious character, thereto.

With attention first directed to the form of the invention shown inFigures l4, it will be seen that a well hole 10 opens laterally into acavity 12. It should be stated at this point that the terms cavity andfissure are used interchangeably throughout the specification andclaims, and are meant to deline any undesirable opening in the formation14 that is in communication with the well hole 10. Since objectionableflows of fluid may pass from the Well hole 10 into the cavity 12, andvice versa, and for other technical reasons, it frequently becomesnecessary to seal olf the cavity 12 from the Well hole 10, particularlywhere the volumetric extent of the cavity is very great.

In order to seal oli:` the cavity 12, it is obvious that the latter maybe filled with a sealing or cementitious material, however, where thecavity 12 is of very large size, this is a very expensive procedure.

In accordance with the present invention, the cavity 12 is first bridgedor sufficient material is lodged therein adjacent the juncture of thesame with the Well hole 10, that such bridging material will constitutea total or partial dam against the passage of sealing material into thecavity, and serve to hold the latter in the mouth of the cavity, so tospeak, to seal the cavity and to allow the material to set if the sameis of a cementitious character.

ln order to accomplish this purpose a plurality of plants 16 arelaterally compressed and inserted root ends first into the lower end 18of a tube 20, while the latter is disposed above the surface of theground. Although it is preferred that the plants be inserted in the tubeas described, it is obvious that the plants, if desired, may be insertedinto the tube through either end thereof root rst, or vice versa. Whileit is though that most types of plants that can be forced into the tube20 will suiiice for the purposes of the present invention, it isparticularly desirable that the plants selected be tough and durable,and that the vegetable libers of the same possess considerableresiliency so that on removal from the tube 20, the plants will expandlaterally. Exemplary of the extremely wide l range of plants that servethe purposes of the invention, the yucca plant, the lechuguilla plant,and the white spruce have been found to work extremely well and possessthe desired characteristics to a high degree. VIn general, all plantspossess the desired characteristics to some extent, and for. particularsizes of tubing 20 andv cavity 12 dimensions, some plants maybe found toserve more satisfactorily than others.

AAfter the plantsv 16 vare pushedinto the tube 20, the tube 20is loweredin the well hole 10 to the-position shown in Figure l, in which theplants 16 in the tube 20 extend from the top of the cavity 12 to thebottom thereof. It is not essential that the well hole extend below thecavity 12 but it is preferred that the well hole extend a short distancebelow the bottom of the cavity 12 so that the plants 16 will extend frombelow the bottom of the cavity 12 to above the top of the same.

Fluid pressure is then applied in the tube 2u to force the mass ofplants 16 from the lower end of the tube 2t), and while the plants 16are being forced therefrom, the tube 20 is raised at a rateapproximately equal to the rate that the plants are ejected therefrom sothat the plants 16 and the tube 2i) assume the positions shown in Figure2, it being noted that upon release of the restraint of the tube 20 uponthe plants 16, the latter have spread laterally into the cavity 16.

The aforementioned fluid pressure may be most easily applied within thetube 20 by having lowered the tube 2t) in the well hole upon a string ofdrilling7 stem 22, the lower end of which is partially shown in Figurel. Mud, Water, or any suitable fluid such as oil may be forced throughthe drill stem 22 and into the tube 2t) to force the plants 16therefrom.

After the plants 16 are positioned as shown in Figure 2, cement slurryor any suitable cementitious sealing material 24 is passed through thetube 20 into the mass of plants 16, it being noted that the plants 16form a skeletal framework for supporting the material 24, and preventssubstantial quantities of the material 24 from passing therethrough andfurther into the cavity 12 or the portion of the well hole below thecavity 12, as illustrated in Figure 3. In other words, the mass ofplants 16 constitute an effective hindrance against the passage ofquantities of sealing material 24 into the cavity 12 substantially inexcess of the amount required to seal off the mouth of the cavity 12.After the sealing material 24 has set and has become suflicientlyhardened to proceed with drilling operations, the portion of the plants16 and the matrix of sealing material 24 therefor disposed in alignmentwith the well hole 10 may be drilled through to form a bore 26 (seeFigure 4) that is effectively sealed olf from the cavity 12.

It will of course be understood that the material 24 need notnecessarily be introduced through the tube 2li, and any otherconventional means for this purpose may be employed.

In order to expedite the above described procedure, the plants 16 may beejected from the tube 20 by the material 24 itself, in which instance,the material 24 will follow the plants 16 from the tube 20 to form amatrix thereabout, as will be apparent to those skilled in the art.

It is not absolutely essential to the present invention that the plants16 be lowered to the position shown in Figure l while still in the tube20, but if desired or deemed expedient for any reason, the tube 20 maybe lowered to substantially the position shown thereof in Figure 2 :L-

with the plants 16 therein, after which the tube 28 is held stationaryand fluid pressure is applied as stated hereinbefore to eject the plants16 downwardly from the tube 20. Upon being ejected from the tube 2% inthis particular manner, the plants 16 will expand laterally while movingdownwardly to the ssure bridging position shown of the same in Figure 2.

Inasmuch as the expanded plants 16 are to form at least a partialbarrier for the material 24, it is preferred that the plants 16 bepacked initially as compactly as possible in the tube 20, and with theleaves, branches, or the like. thereof entangled to a considerableextent to strengthen the barrier formed thereby in the cavity 12.

Attention is now directed to the form of the invention shown in Figures5-7, inclusive. As in Figures 1.--4, the Wellhole is shown at 10, thecavity at 12 and the tube at 20 (partially shown). This form of theinvention differs from the form illustrated in Figures 1 4 primarily inthey character of the bridging material employed and the means speciallyprovided to cause lateral expansion of the bridging material uponejecting the same from the tube.

This form of the invention comprises a resilient inflatable member 28,preferably formed of rubber or similar material, which is provided witha valve inlet 3l) through which air or other expansible fluid may beintroduced into the member 28 under pressure. Indicated at 32 is adeformable mat or screen that is deformable in character, and which maybe formed of woven fibers, metal, or synthetic materials. The member 28is rolled up within the mat or element 32 while deflated and suchelements are inserted in the lower end of the tube 20 with the inlet 28being accessible. The member 28 is then inflated through the inlet 30 toa high pressure and the inlet 30 is then closed. With the member 23 thusinflated, it will be seen that it bears on the element 32 to urgelateral expansion of the latter. A number of elements 32 may beemployed, and if these elements differ in structural strength, thestronger is placed outermost, that is, next to the tube 20.

After the elements 32 and the member 28 are positioned in the tube 20,and after the mel .ber 28 is inflated to be in the relative positionsthereof shown in Figure 5, the tube 20 is inserted into and lowered inthe well hole 10 to a position corresponding to that shown in Figure l,and is then slowly raised while fluid pressure is applied `within thetube 20 to eject the elements 32 and the member 28 therefrom in such amanner that the vertical position of the elements 32 and the member 28is disturbed as little as possible, whereupon the member 28 expands uponrelease of a restraint previously imposed thereon by the tube 20 to theposition shown in Figure 6, wherein it will be noted that elements 32bear against the sides of the well hole 10 immediately above and belowthe cavity 12 with the intermediate portions of the same bulging intothe cavity 12.

With the elements 32 in the position shown in Figure 6, a cementitioussealing material 24 is forced into the interior of the elements 32, thatis, the space previously occupied by the member 28, it being noted thatthe member 28 will either rupture upon expansion into the shape shownthereof in Figure 6 by virtue of its own extension, or by theapplication of pressure thereon by the material 24. Obviously, any othersuitable means, not shown, may be provided for rupturing the member 28if deemed necessary, such as a pointed tool that may be lowered throughthe tube 20.

It will be seen that the elements 32 will constitute a partial barrieragainst the passage of material 24 into the cavity or fissure 12, sothat the material 24 will assume the position shown in Figure 7, whichmaterial 24, upon hardening may be drilled to provide the bore 34therethrough as will be understood.

In the further modified form of the invention shown in Figure 8, springmeans are employed to serve the function of the inflatable member 28used in conjunction with the form of the invention shown in Figures 5-7.In this form of the invention, a screen 36 is superimposed upon a screen38 of greater mesh size. A plurality of elongated spring strips 40 arelaid on top of the screens 36 and 38 and the screens and the strips 40are rolled up in a manner that will be clearly apparent from referenceto Figure 8 to form a roll 42. Obviously, if the roll 42 is rolledtightly, the same will expand laterally if released from restraintholding the same in a tightly rolled condition. The roll 42 isrestrained against lateral expansion and inserted in the tube 20. Theroll 42 is then released from the tube. 20 in the well hole 10 in amanner similar to that in which thev elements 32 were released, asdescribed in connection with Figures 5-7. The roll 42 will besutliciently compact, of course, while seated in the tubev 20 that fluidpressure within the tube 20 will eject the roll 42 therefrom.

Upon release of the roll 42 in the well hole, the roll 42 will unwind tosuch an extent as to seat against the well hole above and below thecavity 12 As in the previously described forms of the invention", acementitious sealing material is formed into the center of the expandedroll 42 to form a seal for the cavity 12 as will be evident to thoseskilled in the art, In the event that the springs 40 are not ofsufficient strength to bulge the screens 36 and 38 into the cavity 12,it will be apparent that the pressure of the cementitious materialapplied to the interior of the roll 42 will serve this purpose.

It will be evident that the use of the springs 40 may` be dispensed withentirely when the screens are formed of a material of suicientresiliency to be self unrolling after being released from the tube.

Since the mat 32 in the form of the invention shown in Figures 5-7, aswell as the screens 36 and 38 of the form of the invention shown inFigure 8 obviously do not have to be in roll form, but may be placed inthe tube in any suitable arrangement so as to expand laterally under theurging of the elements 28 and 40, respectively, upon release from tube,the scope of the invention is not to be considered limited solely to theuse of mats and screens of roll form. For example, the mats and screensmay be of zigzag or accordion shape.

It is also contemplated that in filling the tube with any of the formsof the invention shown in the drawings, chopped, cut, or ground ragsformed of cotton, silk, wool, rubber, or synthetic fibers may also beinserted in the tube either packed in therewith or placed loosely in thetube above the same, so that upon expelling the mass from the tube byfluid, the rags will be forced against the plants, mats or screens (asthe case may be) to further perfect the seal of the fissure bridgedthereby. In fact, it is thought that such rags may be inserted andtightly packed in the tube in lieu of the bridging constructions shownin the drawings.

From the foregoing, the method of the invention and the nature ofapparatus suitable for use in practicing the method of the inventionwill be readily understood and further explanation is believed to beunnecessary. However, since numerous modifications and changes willreadily occur to those skilled in the art after a consideration of theforegoing specification and accompanying drawings, it is not desired tolimit the invention to the exact apparatus shown and method described,but all suitable modications and equivalents may be resorted to, fallingwithin the scope of the appended claims.

Having described the invention, what is claimed as new is:

1. For use in bridging a fissure in a well hole, a tube and deformablefissure bridging material slidably disposed therein, and spring meansdisposed within the deformable material and also within the tube forurging lateral expansion of the deformable material, whereby the springmeans will expand the deformable material laterally to a size exceedingthe outside diameter of the tube upon the material when said means isejected from the tube.

2. For use in bridging a issure in a well hole, a tube and deformablefissure bridging material slidably disposed therein, and a resilientinflatable member disposed within the deformable material and alsowithin the tube, whereby the member may be inflated with an expansibleiluid to urge lateral expansion of the bridging material when ejectedfrom the tube,

3. A method for bridging a fissure in a well bore comprising applying aconfining compressive force against an inherently resilient elongatedbody of material normally tending to expand laterally to therebyrestrain the body against lateral expansion and hold it in a relativelynarrow mass, introducing the body while in the confined state into awell bore to a position opposite the fissure and thereafter releasingthe restraining and conining force to allow the body to expand laterallyto its normally uncontined state whereby to expand and bridge theiissure.

4, A method for bridging a issure in a well bore cornprising applying aconfining compressive force against an inherently resilient cluster ofelongated discrete bridging elements normally tending to expandlaterally to thereby restrain the cluster against lateral expansion andhold it in a relatively narrow mass, introducing the mass while in theconfined state into a well bore to a position opposite the ssure,releasing the restraining and confining force to allow the cluster toexpand laterally to its normally unconiined state to provide a skeletalbridge across the fissure and then introducing a cementitious materialinto said well bore and into and upon said skeletal bridge to establisha seal across said fissure.

5. A method for bridging a ssure in a well bore comprising providing aninherently resilient generally tubular body provided with a filler ofloose cement and normally tending to expand laterally, applying aconfining compression force against said resilient tubular body and itsfiller to thereby restrain the body and its filler against lateralexpansion and hold it in a relatively narrow mass, introducing the bodyWhile in a confined state into a well bore opposite the issure andthereafter releasing the restraining and confining force to allow thetubular body and the cement iller to expand laterally to its normallyunconned state whereby to expand and bridge the fissure.

References Cited inthe le of this patent UNITED STATES PATENTS 1,716,925Loomis June 11, 1929 2,064,936 McQuiston Dec. 22, 1936 2,079,517McQuiston May 4, 1937 2,100,684 Carroll Nov. 30, 1937 2,216,067 ClarkSept. 24, 1940 2,504,462 Sprague et al Apr. 18, 1950 2,577,610 DeupreeDec. 4, 1951

